Starches generally contain two types of polysaccharides (amylose and amylopectin) and are classified as carbohydrates. Some starches are pregelatinized, typically through thermal means. Generally, pregelatinized starches can form dispersions, pastes, or gels with cold water. Pregelatinized starches are generally digestible and have been used in a number of ways, including as an additive to a variety of food products (e.g., in baking, snacks, beverages, confections, dairy, gravies, prepared foods, sauces, and meats) and in pharmaceuticals.
Another use for pregelatinized starches is in the preparation of gypsum wallboard. In this regard, during manufacture of the board, stucco (i.e., calcined gypsum in the form of calcium sulfate hemihydrate and/or calcium sulfate anhydrite), water, starch, and other ingredients as appropriate are mixed, typically in a pin mixer as the term is used in the art. A slurry is formed and discharged from the mixer onto a moving conveyor carrying a cover sheet with one of the skim coats (if present) already applied (often upstream of the mixer). The slurry is spread over the paper (with skim coat optionally included on the paper). Another cover sheet, with or without skim coat, is applied onto the slurry to form the sandwich structure of desired thickness with the aid of, e.g., a forming plate or the like.
The mixture is cast and allowed to harden to form set (i.e., rehydrated) gypsum by reaction of the calcined gypsum with water to form a matrix of crystalline hydrated gypsum (i.e., calcium sulfate dihydrate). It is the desired hydration of the calcined gypsum that enables the formation of the interlocking matrix of set gypsum crystals, thereby imparting strength to the gypsum structure in the product. Heat is required (e.g., in a kiln) to drive off the remaining free (i.e., unreacted) water to yield a dry product.
Often, pregelatinized starches add water demand to the process. To compensate for the water demand and allow for sufficient fluidity during manufacture, water content must be added into the stucco slurry. This excess water creates inefficiencies in the manufacture, including increased drying time, slower manufacturing line speeds, and higher energy costs. The inventors have found that pregelatinized and partially hydrolyzed starch demands less water.
The inventors have also found that techniques for preparing pregelatinized, partially hydrolyzed starches have not been fully satisfactory. Conventional methods for preparing such pregelatinized, partially hydrolyzed starches have not been efficient, with low output and slow production, as well as high energy costs. Thus, there is a need in the art for an improved method of preparing pregelatinized, partially hydrolyzed starch, particularly exhibiting low water demand.
It will be appreciated that this background description has been created by the inventors to aid the reader, and is not to be taken as a reference to prior art nor as an indication that any of the indicated problems were themselves appreciated in the art. While the described principles can, in some regards and embodiments, alleviate the problems inherent in other systems, it will be appreciated that the scope of the protected innovation is defined by the attached claims, and not by the ability of the claimed invention to solve any specific problem noted herein.